Answer:
3284.3 kg is the mass of HCl needed to produce 5000 kg of CaCl₂
Explanation:
This is the reaction:
CaCO₃ + 2HCl → CaCl₂ + CO₂ + H₂O
Let's convert the mass of the product to moles (mass (g) / molar mas)
Firstly we must convert kg to g
1 kg = 1000 g
5×10³ kg . 1000 g / 1 kg = 5×10⁶ g
5×10⁶ g / 110.98 g/mol = 45053.1 moles
Ratio is 1:2 So, let's make a rule of three:
1 mol of CaCl₂ was produced by the use of 2 moles of HCl
So 45053.1 moles of salt, were produced by, the double of moles
45053.1 mol . 2 → 90106.2 moles
Let's convert the moles, to mass (mol . molar mass)
90106.2 mol . 36.45 g/mol = 3284375 g → 3284.3 kg
Thermometer D, because it measures accurately to the tens place. Hence, option B is correct.
<h3>What is temperature?</h3>
The degree of hotness or coldness is measured on a definite scale.
Accuracy: It is defined as the closeness of a measured value to a standard or known value.
For Example: If the mass of a substance is 50 kg and one person weighed 48 kg and another person weighed 55 kg. Then, the weight measured by the first person is more accurate.
Precision: It is defined as the closeness of two or more measurements to each other.
For Example: If you weigh a given substance five times and you get 1.8 kg each time. Then the measurement is said to be precise.
The level of precision is determined by the maximum number of decimal places.
As per the question, the thermometer D has markings 40°, 45° and 50° at equal intervals and there are four small markings equally spaced in between the numbers and thermometer D has markings 40°, 45° and 50° at equal intervals but there are no small markings equally spaced in between the numbers. That means thermometer D measures temperature more accurately than thermometer C.
Thermometer D, because it measures accurately to the tens place. Hence, option B is correct.
Learn more about the thermometer here:
brainly.com/question/14900550
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Answer:
Kw = 2.88 × 10⁻¹⁵
Explanation:
Let's consider the dissociation of water.
H₂O(l) ⇄ H⁺(aq) + OH⁻(aq)
The equilibrium constant Kw is:
Kw = [H⁺].[OH⁻]
If pH = 7.27, we can find [H⁺]:
pH = -log [H⁺]
H⁺ = anti log (-pH) = anti log (-7.27) = 5.37 × 10⁻⁸ M
According to the balanced equation, 1 mole of H⁺ is produced per mole of OH⁻. So, [H⁺] = [OH⁻] = 5.37 × 10⁻⁸ M
Then,
Kw = [H⁺].[OH⁻]= (5.37 × 10⁻⁸)² = 2.88 × 10⁻¹⁵
